Protracting square



May 15, 1923.

M. BROWN PROTRACT ING SQUARE Filed Jan. 6, 1921 Illlllllllll Patented May 15, 1923,

UN'FE@ MILO BROWN, OF ANDERSON, INDIANA.

PROTBACTING SQUARE.

Application led January 6, V1921. Serial No. 435,437.

T @ZZ w zom t may concern Be it known that l, Miro BROWN, al citizen of the United States, residing at Anderson, in the county of Madison and State of Indiana, have invented certain new and useful improvements in Protracting Squares, of which the following is a specification.

This invention relates to a yprotracting or indicating square for use in determining the error in a square measurement.

An important object of the invention is the provision of a protracting square which is self-adjusting,`and upon application to an object will show the degree of error, or

precision in the angular dimensions of such object.

A further objectof the invention is the provision of a device of the above described character, which is so constructed as to make it of practical use for carpenters7 or other skilled workmen.

Other objects and advantages will be apparent during the course of the following detailed description.

In they accompanying drawings, forming a part of this specification, and in which like reference characters designate like parts throughout Vthe same:

Figure 1 is a. side lelevation of the improved yprotracting square, showing the face thereof.

Figure 2 is a side elevation o-f the improved protracting square.

Figure 3 is a rear elevation of the improved protracting square showing the association of the various parts thereof.

Figure 4; is a plan view of the improved protracting square.

Figure 5 is a. Jfragmentary sectionaly View of the protracting square showing the various cooperating elements thereof.

Figure 6 is a plan view of a detail embodied in the protracting square.

Figure 7 is a cross sectional view taken on the line 7 7 of Figure 1.

In the drawings, wherein for'the purpose of illustration is shown a preferred embodiment of my invention, the letter `A rdesignates the stock of a. square, having the blade B rigidly mounted thereon; and upon which blade B, the blade C is pivotally mounted, as by detachable means D.

The lstock A is of ordinary construction comprising a relatively thick piece of hard wood or steel having its edges bevelled as at 10; and provided with the slotted recess 11 in one end thereof.

The blade B is preferably of steel and relatively thinner, than the stock A, and has an end 12 thereof disposed within the slot 11 in the stock,fand rigidly secured thereto by aI rivet 13 extending laterally and entirely through the thickness of the stock A, and by .a rivet 14 extending laterally through one side of the stock A rand engaging the blade B in such manner that the slot 11 upon one side of the rigidly mounted blade B remains unobstructed for the free reception of the blade C and which will behereinafter more fully described. It is preferred that a longitudinal edge 15 of the blade B be disposed at exactly a right angle to the inside edge 16 of the stock A, the relation of the stock A and the blade B in reality being that of the ordinary carpenters square. The blade B is provided centrally of its longitudinal length with an aperture 18, and providedy with aligning indicating marks 19 and 20, upon each side of the aperture 18, and which indicating marks are aligned substantially parallel with the edge 15 in such manner that they intersect the edge 16 of the stock A at a right angle.

The' blade C is relatively greater in width than the blade B and is provided with an aperture 21 therein, adapted to align with the aperture 18, whereby the bladeC can be pivo-tally mounted upon the blade B by the detachable means D. The blade C' is preferably .provided with a projecting end 22 adapted for reception within the slot `11 'of the stock A, said projection 22 however, not extending the entire width of the blade C, but having a. face 28 inclininginwardly from the outer end of the-blade and adapted to abut against the side 24 of the stock A, when the blade C is in one o-f its extreme positions; The slot 11 is of peculiar formation, and is provided with an extension 25, adapted to receive the end 26 of the blade C'lying adjacent the projecting end 22. Thisconstruction is provided, in -0rder that a secure and stable square is provided by the stock A and blade, B, upon which the blade C may be p-ivotally mounted to withstand the rough usage sometimes given or necessarily imposed upon the tools workmen.

The blade C provided with slots 30 @9 clamp the bladeC to the blade B either for v denotes a gra-de,

and 31 concentric with the aperture 21,

and upon each side thereof, which slots areprovided inithe bodyfof they blade C transversely to the longitudinal run of the blade.

The slots and 31 are provided with graduations 32 and 33 respectively, it be any special system of angular measurementmay beincorporated adjacent either of the slots 30 .or 31,-to suit the requirements` of thetrade or'profession adopting the protracting square. f Slots 35 and 36 .are `pro'- vijded upon thevopposite sides'of the Yslots 3 0 land 31E respectively to the graduated portiensthereof, and adapted to receive rivets or guiding lug-s 37 and 38 respectively, hav- I ingI suitable headsfthereon'adapted to guidey y the movement of the blade C in its pivotal movement over the blade B; The slots 35 ald are concen-tric with the yaperture 21, and of course, lie in parallel relation to the slotsxO andll respectively'. When the blade C-"is disposeduponthe blade B, a

portion 401 will project yinwardly from the side 15T of the blade B,-the purpose of which will hereinafter be more fullyt described. It is preferred-'tiraban end 4'1 projectsfrom the eiid-42 ofthelbladeB, and that a longitudinal edge48 projects upon theopposite side of the "bladeB vfrom the projecting portion 40. In this arrangement, the'blade C, en'- tirely overlies the blade B,- at alltimes, even in itsmost extreme positions:

The detachable v'means D'includes the pivot pin or Arivet 45, provided with a screw threaded ,end 146, the said pin 45 being adapted for-pivotal insertion through the apertures--lwand-QlV ofthe bladesB and C re? spectively. The screw' threaded end46 projects from-'the faceo'f' the blade'C, and receivesthe -lock'washerl 47: thereon. The lock washer is of-peculiarformation, and-is pro-E yvidedywith theape'rture48 for 'free insertion over theV pivotl pin 45,Vandf'with'extending l,eaves v4%).whichy are suiiici'ently? resilient to provide-"a loclewasher whichf'will havel yan Qenclamping action upon theface of the blade ,C. A thumb nut 50 isprovided for engaging with thescrew threads ofthe end 46- and `adapted to compressfthe. resilient lock vwasher 47,-1Whereby they same" may pivotalmovemento'r rigidly inone position; .j .;,I-n1`order tooperate,the bladel C ispivot-vv aflly': disposed uponV4 the blade B'by kthe de= f tachable means D, in such mannen that the indicator -marks-f 19'fand 2O'willi1be visible throughthe slots and 31 respectively. yln

order to test the accuracy of any object the i sides of-whicli should lie Aat exactly. 900 to each other, the stock A isv positioned upon one side andthe Vsame drawn thereover, until the fo'rwardtedge 51 of the bladel C abuts the adjacent side of said object the said edge 51 willconform-tothe plane ofthe side of the object which it is measuring, throughout its length. vShould one side of the object be'out orlv alignment withrespectA to the other and form an anglegreater than 90C the blade C will swing into a positiony substantially as illustrated inFigure 5 of the drawings, and the discrepancy inthe angular measurement between the I sides `of the objectwill be'indicatedfupon vthe gradu-r ations `32 or 33, by the indicator markslQ andi-20. v

ln normaly position, thel edge 51 of the blade Vlie's at yexactly right angles'fto; the p edge 16 ofthe stockA A, and in which posi-1 tion'the zero marks ofboth'thegraduations 32 and 83, ylie in longitudinal alignment with thel indicator marks 19" and 20j Thus it' can be seen that any variance in the angle measurement asy indicated by the'edges` 16 and 51,will be instantly-*measured upon both of the scales'32 or;v 33 by the indicator marksl 19A and 20.y It'yis of course, optionalwhich of the graduated measurements@foris" used, since either one vor both may bei 'sup- ,j planted by-'other methods of angular nicas# f urement.'r Attention is vcalled-,tothe fact that the end 26" has been `so constructed-that v it will not'ride out ofthe rextendedportion 25oftheI slot211,fthus'doing away with any. liability of chips, or other'foreigneniaterial getting=into the lslot land interfering with the pivotal operation .of the blade'C,

Should it be ldesired to do away with th self adjusting: feature as provided l by! the pivoted blade C, the nut 50l can be tightened uponthev pivot pin' 45,l forcing thefwasher 47 into secure' clamping engagement with the face of the blade-"C, thus rigidly'an'd securely binding thev blade 'C to the'jbla'de B to indicate an angle of 900 intermediate the edgesf'ly and 15, or infact a greater-'or a less angle'ias desired. v Y .Y

It is yto be understood thatl theform'of my invention herewith` shown and described is to be taken 'as ai preferred example of ythe same', and that various ch'anges'in thefsha'pe, size and arrangement of parts may be r'e'l sorted to, rwithout departing from the lspirit of-'theinve'ntion or the scope of: the'fsubl joined claims.

'l' claim '1. Ina protracto'rglthe combination offa` stock, a blade rigidly'mounted upon said stock and having an indicator markithereon, lasecon`-d blade relatively wider than f said rigidly mountedy blade,l detachable-means pivotally mounting said; Widerxfblade upon said ,rigidly mounted'blade, and centrally thereo'l, said wider blade having graduations thereon adapted to cooperate with said indicator mark upon the rigid blade for indicating the angle between the two blades, and guiding means for lin'iiting movement of said pivoted blade. y V

2. In a protracting square, the combination of a stock, a blade of less thickness than said stock, said blade rigidly mounted upon said stock and having indicator marks thereon, a second blade wider than said first mentioned blade pivotally mounted upon said rigidly mounted blade and having slots therein adapted to expose the indicator marks upon said rigid blade, said pivoted blade having graduations adjacent said slots, and guiding means for said pivoted blade.

3. A protracting square comprising a stock, a blade rigidly mounted with respect to said stock, said blade having an indicating mark thereon, and a second blade-pivotally mounted upon the rigidly mounted blade and having a slot therein adapted to expose the indicating mark upon said rigidly mounted blade, said pivotally mounted blade having graduations thereon adjacent a mar ginal edge of said slot adapted for cooperation with said indicating mark upon the rigidly mounted blade for measuring the angle between the two blades.

4. In a protracting square,the combination of a stock, a blade rigidly mounted on an end of said stock substantially at right angles thereto, and a second blade pivotally mounted upon saidl trst mentioned blade substantially midway of the stock and the free end of said firs-t mentioned blade, said second mentioned blade being adapted for oscillation upon said first mentioned blade and when in alignment therewith having a longitudinal edge portion thereof normally extending outwardly of the adjacent edge of said first .mentioned blade, and means on said blades for determining the relative angular relation of the same.

MILO BROWN. 

